In recent years, attention has been given to depositing layers, especially in the field of semiconductor or IC fabrication. Deposition is a step in IC manufacturing. During deposition, a layer of, for example, either electrically insulating (dielectric) or electrically conductive material is deposited or grown on a silicon wafer. One type of deposition is Chemical Vapor Deposition (CVD). CVD is used to deposit films that function, for example, as dielectrics (insulators), metals (conductors), or semiconductors (partial conductors) on a substrate. During the CVD process, precursor gases that contain atoms of the material to be deposited may react on the substrate surface, forming a thin film of solid material.
One form of CVD is Plasma Enhanced Chemical Vapor Deposition (PECVD). PECVD is used as a deposition method for semiconductor fabrication for mainly depositing dielectric thin films from a gas phase (vapor) to a solid state on some substrates. There are some chemical reactions involved in the process which occur after creation of a plasma of the reacting precursor gases.
As IC technology is getting advanced, in CVD and PECVD there exists a need to provide films with controlled surface roughness. A smooth surface is desired because it may allow for a good result in a photolithography process. There also exists a need to provide films that are defect-free, and to provide films that adhere to the host substrate. Furthermore, there exists a need to provide films that are uniform in thickness, as well as in chemical, electrical, and mechanical properties.
It may further be desirable to eliminate, or at least to reduce, film roughness at Premetal Dielectric (PMD), Intermetal Dielectric (IMD) and Passivation modules in a substrate process flow. It may further be desirable to improve defect monitoring, such as for example in-line substrate defect monitoring provided for by KLA-Tencor Corporation. It may further be desirable to provide for a smooth surface of dielectric layers.